REMAR_CITIZEN - Bringing people together for the conservation and sustainable fishery of mangrove crabs:
● In Brazil, tens of thousands of people depend on the collection of the mangrove crabs Ucides cordatus and Cardisoma guanhumi. The management of the artisanal fishery of these important natural resources faces several problems, such as the difficulty of establishing adequate capture bans during so called andada events, periods of mass-mating. During andada, the crabs are extremely easy to capture, not just by professional artisanal fishers but by everyone, compromising the sustainability of their fishery.
● Andada of U. cordatus typically occurs around either new moon, full moon, or, occasionally, around both phases moon phases, during 3 to 4 months between November and April. Between 2003 and 2019, decision-makers have prohibited capture precautionary always at both full and new moon, due to a lack of understanding of the drivers of the temporal occurrence of andada, and the need to disclose the capture bans in advance of the reproductive season. When no andada took place during a ban, this resulted in critical income losses for the artisanal fishers and conflicts, in addition to wasted public resources for unnecessary policing.
● Regarding C. guanhumi, the problem is even greater, due to a complete lack of knowledge of its reproductive rhythms.
● In 2013, REMAR – The Network for the Monitoring of Reproductive Andadas of Crabs - was created, scientifically coordinated by Edinburgh Napier University and the Federal University of Southern Bahia. REMAR investigates the linkage of the reproductive rhythm of the crabs with geophysical cycles, to guide the establishment of (biologically and societally meaningful) capture bans, and thereby promote sustainable fishery, help conserve the species and avoid socioeconomic problems.
● REMAR unites researchers from Scotland (Edinburgh Napier University), Amapá (UEAP), Pará (UFPA and RESEX de Soure / ICMBio), Paraíba (UEPB), Sergipe (UFSE), Bahia (UFSB), Espírito Santo (UFES), Paraná (UFPR) and Santa Catarina (UFSC). REMAR monitored andada events at standardized days during the reproduction period of U. cordatus, using a rapid assessment method. REMAR has also developed a tool that allows a robust forecast of the moon phases that these crabs will likely perform andada in future years. Since 2020, REMARs forecasts have been used by the government for the preparation of normative instructions for the suspension of capture of U. cordatus, during its reproductive season in North and North-eastern Brazil.
● In 2017, the smartphone application REMAR_CITIZEN was launched, which allows people anywhere along the Brazilian coast to record occurrences of andada. Via the app, information provided by crab fishers and traders, protected area managers, policing staff, other researchers, tourists and local residents is sent to the REMAR data server. The use of the app by these citizen scientists is fundamental for the evaluation and improvement of the predictions of future andada events and the regulations for suspending crab capture in future years. Metadata of information received by the app can be viewed on a publicly accessible web page.
● This citizen-science initiative is expected to contribute to the perpetuation of an ancient fishery culture, to the reduction of public spending for fisheries management, to the conservation of crabs, to the sustainability of the fishery and to the improvement of the quality of life of traditional populations.